One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,8)(5,6)(9,10)(11,12)(13,16)(14,15)(17,19)(18,20)(21,22)(23,24)(25,26)(27,31)(28,36)(29,33)(30,35)(32,37)(34,38)(39,40) involution — undirected(2,6)(3,8)(10,15)(12,19)(16,22)(20,24)(25,27)(26,30)(28,34)(29,35)(31,33)(32,38)(36,39)(37,40) involution — undirected(1,3)(2,4)(5,8)(6,7)(11,17)(12,19)(13,21)(16,22)(25,26,29,33)(27,30,35,31)(28,36,37,32)(34,39,40,38)(1,4)(2,3)(5,7)(6,8)(9,11,14,17)(10,12,15,19)(13,18,21,23)(16,20,22,24)(25,26)(27,30)(28,32)(29,33)(31,35)(34,38)(36,37)(39,40)(1,2)(3,4)(5,6)(7,8)(9,12)(10,11)(13,20)(14,19)(15,17)(16,18)(21,24)(22,23)(25,27)(26,31)(28,34)(29,35)(30,33)(32,39)(36,38)(37,40) involution — undirected(1,4)(2,3)(5,7)(6,8)(9,13,14,21)(10,16,15,22)(11,18,17,23)(12,20,19,24)(25,28,29,37)(26,32,33,36)(27,34,35,40)(30,38,31,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.